Wireless radio frequency spectrum is a precious and scarce resource for wireless operators in any wireless system. Accordingly, efficient usage of the spectrum is always desired for wireless operators. In particular, Medium Access Control (MAC) overhead efficiency is a key factor to achieve spectrum efficiency. MAC overhead in wireless systems includes packet headers, control and management packets, security context, message authentication code, etc. Reducing MAC overheads as much as possible can significantly improve MAC efficiency and thus conserve wireless resources.